Process of vulcanization.



m. 876.431.. PATIENTEDIJAN, 14, 1908.

A. O. BOURN. PROCESS OF VULOANIZATION.-

APPLICATION FILED DEC. 24. 1900.

To all whom it mcwconcern: a

UNITED STAT AUGUSTUS O. BOURN/GF BRISTOL, RHODE ISLAND.

success on VULCANIZATION.

Application filed December 24,1900. Serial No. 40.926.

vBe it known that I, AUGUSTUS 0. Bonus, a citizen of the United States,residing at Bristol, in the county-of Bristol and State of Rhode Island,have invented a certain new and useful Process of Vulcanization, ofwhich the followingis as ecification.

My inventionre ates to a new and improved process of vulcanization, andhas for its object to provide an improved process of vulcanizingindie-rubber and similar or allied gums, andmy-invention consists in theimproved process or mode of procedure, utilizing the materials set forthin substantially the manner hereinafter described, for producing theresults described. y

Referring to the drawing forming part of this specification I haveillustrated therein one means by which my improved process maybe-carried out, in which there is shown in cross-section a vesselor-chamber in which the vulcanization takes place, togetherwithconnections for sup lying the same with heat, and means for app yingpressure to air.

Articles or substances have heretofore been vulcanized chiefly byexposing them to a high degree of artificial heat m a heated chamber,Without ressure to the action of steam in a closed c amber at a pressureconsiderably above the atmospheric pressure; between heated plates at agreat pressure; and also under ressure in molds. The, pressure thusappliec both strengthens the rubber compound and shortens the periodrequired for vulcanization. There are many articles, however, which itis impracticable to vulcanize in either of the latter three mentionedprocesses, and such articles are usually vulcanizcd in a heated chamberwithout pres sure. Among them might be mentioned boots and shoes,especially such as have a bri ht surface produced by the application ofvarnish before vulcanization.

Broadly stated, my invention consists in a process of vulcanization inwhichthe articles or substances to be vulcanized are exposed to theaction of atmos heric air, whereby the advantages derived rom curingunder ressure in the methods heretofore employee are secured for sucharticles-or substances as have been usually vulcanized in a heatedchamber without pressure. Also many articles heretofore' vulcanized insteam as hereinbefore described can bejtreated by my process with betterresults.

vIn.carrying.eut my invention it is not Specification of Letters Patent.

Patented. Jan. 14, 1908.

necessary that the air sr ould be heated to so ,high a temperature as isnow employed in heated chambers without pressure, in order that'theprocess of vulcar iization maybe accomplished in a reasonable time Whilethe- .de we of tem erature ma var within com- 5% 7 (If 3 Y paratively wie limits, depending upon many ircumstances, as the characteroi thearticles or substances being vulcanized, the pressure of the air. I havefound that a temperature varying from 220 to 300 F. is satisfactory inmost instances: It is also desirable that the air should be underpressure consider ably greater than atmospheric pressure, andgreaterthan the pressure due to theexpansion by heat, and while the degree ofpressure may vary within comparatively wide. limits,

depending upon the specific ap'lication of:

.the process to particular artic es or substances under varyingconditions, I have foundthat a pressure of from 5 to 100 pounds persquare inch is-satisfactory.

Referring now to the drawing, wherein I have illustrated a form ofapparatus which I have used in carrying out my invention, there is aretort or chamber or receptacle, 1, which is preferably made of metal,and this cham- Y ber is of a shape and size adapted: to receive one ormore of the articles or materials to be vulcanized, and is closed insome suitable manner, as by a door, 2,Which in the present instance isadapted to closely fit the opening of the chamber and to be securedthereto in any suitable way, as by bolts, 3,so as to make the chamber orretort airor gastight. The chamber 1, is surrounded by an outer-jacket,4-, which in the present instance is formed tegral with the chamber, 1,and incloses the sides and one end of the chamber, forming space, 5,between the walls of the chamber and the jacket, 4 and this constructionfurnishes a convenient means for heating the Connected to the chamber,1, is a pipe, 10,

which is also connected to some suitable source of su(pply of air, and ihave shown'it as oonnecte to a ump,11, and as being suppliedwith suitablstop-cocks, 12, i3, and a relief valve, 14, by means of which air may besupplied to the chamber, 1, under suitable derstood from what has beenstated, and it' may be said that the article or articles to bevulcanized represented as .r, are placed upon tlghtly the platform, 15,and the closed and the pump being set in operation the air is suppliedto the chamber,'1, under the desired pressure, and steamer other heatedmaterial is supplied through the pipe, t), to the space, 5, so as tomaintain the door, 2,

air at the desired temperature. These sources I of supply can beproperly regulated by the C cocks or otherwise and the articles or sub-Q expansion by heat, and gradually heating the stances are vulcanizedand then removed from the chamber and the operation is repeated. It, ofcourse, follows that there 5 no air pressure within the chamber at tlietime that the articles are inserted, and it is 3 only after the chamberis closed that the air is subjected to pressure above that of theatmosphere and gradually raised, and this raising of the pressure willdepend upon the relative sizes of thevulca-nizer and the pump. v[t

will further be evident that the aircannot atature maintained can beregulated and va" ried according to circumstances at about the huntsabove set forth, and the pressure on name to this specification in theis better to vulcanize at a relatively low temperature and high pressurethan at a relatively high temperature and low pressure.

When both temperature and pressure are for most articles.

I claim as my invention,

1. The process of vulcanizing consisting in exposing the articles to theaction of a surrounding body of air, gradually increasing thetemperature of the air, and also gradually increasing the pressure ofthe air to a pressure above that resulting from expansion by heat. I

2. The within described process of vulea'nizing consisting in subjectingarticles to a surroundingbody of air,increasing the pressure of the airto a pressure above that due to high the vulcanization proceeds toorapidly air to a v ulcanizing temperature.

3. The within described process of Vulcanizing articles consisting insubjecting the same to a surrounding body of air, gradually heating theair to a vulcanizing temperature, and imparting pressure to the air inexcess of that due to expansion by heat.

4. In the vulcanization of vulcanizable compounds, subjecting articlesmade of such compounds to the action of a body of air the pressure andtemperature of which is gradu ally increased, and thereafter reducingthe pressure before the operation is completed.

In testimony whereof I have signed my two subscribing witnesses.

AUGUSTUS O. BOURN. Vi tnesses:

FRANK It. MQKENNA, Aueus'rus O. BOURN, Jr.

presence of

